Replacement for string-as-unibyte function

Replacement for string-as-unibyte function

[Joe Riel]

As of 26.1, string-as-unibyte is deprecated.  The suggested 
replacement is encode-coding-string.  What coding-system should
be passed to that function to get the equivalent result?

-- 
Joe Riel

Re: Replacement for string-as-unibyte function

[moasenwood--- via Users list for the GNU Emacs text editor]

Joe Riel wrote:

> As of 26.1, string-as-unibyte is deprecated. The suggested
> replacement is encode-coding-string. What coding-system
> should be passed to that function to get the
> equivalent result?

Good question!

That should be improved in the docstring!

No idea actually ...

(let ((multibyte-string (string-to-multibyte "Test string.\n")))
  (string=
   (string-as-unibyte    multibyte-string)
   (encode-coding-string multibyte-string 'utf-8-unix) )) ; t

-- 
underground experts united
http://user.it.uu.se/~embe8573
https://dataswamp.org/~incal

Re: Replacement for string-as-unibyte function

[Eli Zaretskii]

> Date: Sat, 30 Jan 2021 16:34:10 -0800
> From: Joe Riel <joer@san.rr.com>
> 
> As of 26.1, string-as-unibyte is deprecated.  The suggested 
> replacement is encode-coding-string.  What coding-system should
> be passed to that function to get the equivalent result?

Please describe your use case: what are you trying to do that you
needed string-as-unibyte?

Replacement for string-as-unibyte function

[Joe Riel]

Apologies for this partial duplicate; after posting realized I no longer
receive email from this group, so renewed.  Am copying and responding to response
from the website:

Eli Zaretskii asks:
> Please describe your use case: what are you trying to do that you
> needed string-as-unibyte?  

Am handling a message passed in from an external process
(its passed in chunks).

The header of the message specifies its length, in bytes.
Some of the characters may be unicode.   Am using
buffer-substring-no-properties to later extract the message.
To get its length write, each byte has to be a character in the buffer.

It appears as though

   (encode-coding-string string 'utf-8-unix)

is the equivalent of (string-as-unibyte string).


-- 
Joe Riel

Re: Replacement for string-as-unibyte function

[Eli Zaretskii]

> Date: Sun, 31 Jan 2021 15:02:27 -0800
> From: Joe Riel <joer@san.rr.com>
> 
> Eli Zaretskii asks:
> > Please describe your use case: what are you trying to do that you
> > needed string-as-unibyte?  
> 
> Am handling a message passed in from an external process
> (its passed in chunks).
> 
> The header of the message specifies its length, in bytes.
> Some of the characters may be unicode.   Am using
> buffer-substring-no-properties to later extract the message.
> To get its length write, each byte has to be a character in the buffer.

Then the text you get is already unibyte, and I see no reason to use
string-as-unibyte.  Just read the text into a unibyte buffer and
process it there, then _decode_ everything when you want to present it
or process it as human-readable text.

IOW, I don't see why you'd need string-as-unibyte in this scenario.